1. Technical Field
The present invention relates generally to boat dollies; and, more particularly, to an improved boat dolly characterized by its mobility, stability, ruggedness, and durability and which is especially suited for: (i) rapid on-loading of commercial fishing boats and the like from either an off-shore floating or a beached position reasonably proximate to a boat storage marina or yard; (ii) over-land transport from the point of on-loading to the marina storage facility; and (iii), rapid off-loading of the boat and placement on suitable storage blocks or the like--and, wherein each boat dolly is capable of handling a relatively high number of boats per day and transporting the same between either an off-shore floating or a beached position and a permanent or semi-permanent storage site during the off season. For example, commercial fishing boats of the type commonly used in such fisheries as the Alaskan fishery are generally relatively large vessels ranging in weight from about 10,000 pounds to on the order of about 30,000 pounds or more. At the conclusion of each fishing season, the owners of such boats will normally have the vessels hauled to a suitable boat yard or marina for dry storage, maintenance and repair, with such boats again being launched shortly prior to the next fishing season. There are, of course, a limited number of suitable accessible storage yards and/or marinas capable of handling vessels of this type; while, at the same time, when a given fishing season ends, the captains, crews and owners of each boat in the fishing fleet are interested in having their boats hauled out of the water and transported to a suitable point of dry storage as rapidly as possible in order that the crew can return home. As a consequence, at the conclusion of any given fishing season, the owners and/or managers of boat storage facilities find themselves suddenly inundated by a large number of boats, all of whose crews demand immediate service so as to expedite their return home. When using mobile boat dollies incorporating the features of the present invention, such marina and/or boat yard personnel find that they can readily handle the demands for immediate service from a large number of boat captains, crews and/or owners since any given boat dolly is fully capable of handling several dozen boats per day irrespective of differences in boat sizes and designs and irrespective of tidal and/or wind conditions assuming only that the ultimate dry storage site is located in reasonable proximity to the launch ramp or other location where the boat is to be hauled and loaded on the trailer.
2. Background Art
Many different types of mobile boat dollies have been designed and used over the years for handling all types and sizes of boats ranging from relatively small private pleasure boats up to relatively large commercial fishing boats. Generally, the handling of pleasure craft does not present a significant problem for boat storage facilities since many boat owners own their own mobile boat trailers and provide their own storage facilities; while those who do require services and support by storage marinas and/or boat yards are generally able to fit within a work schedule wherein delays measured in hours, days or even longer are not critical and will not result in loss of business for the marina or boat yard. In the commercial fishing business, on the other hand, the boats are generally used until virtually the last minute prior to conclusion of the fishing season; and, when the season ends, it is imperative that the marina and/or boat yard be able to accommodate the needs of the boat owners and/or crews, all of whom are interested in having their boat hauled and stored as rapidly as possible in order that the crew can return home after prolonged absences of many weeks and/or months. In those instances where a marina finds itself unable to accommodate a large number of boats on a given tide, the crews of those boats who cannot be immediately accommodated will often seek alternative storage facilities even though such alternative facilities may be less convenient rather than having to wait until the next tide or day. To minimize this problem, some of the larger marinas and/or boat yards have tended to acquire and maintain extra dollies and boat handling personnel so as to be able to meet peak demands; but, of course, this "solution" requires significant capital investment in boat handling equipment and in manpower-- steps that are not economically justified during non-peak periods.
A wide variety of different mobile boat trailers have been designed and tried over the years. Typical of the designs are those shown in, for example, U.S. Pat. Nos. 3,822,899--Slack and 4,232,879--Boxrud. Thus, in each of these patents, there is disclosed a tandem axle boat trailer having a generally rectangular or box-like rigid frame with fixed support means in the form of fore and aft port and starboard boat support pads of the like. In each case, the boat trailer is designed to be backed into the water and at least partially submerged, with the boat to be hauled then maneuvering over the trailer and boat supports so that when the trailer is pulled out of the water, the boat is supported thereon and capable of being transported to a suitable storage site. In the Slack patent, the patentee provides an adjustable bow support bracket and port and starboard locating markers which can be used to facilitate positioning of the boat over the submerged or partially submerged trailer. The Slack trailer is further provided with a plurality of fixed, rigid, transverse support beams or tie bars which are common to most boat trailers; but, which tend to make it difficult and time consuming to off-load the boat from the trailer onto suitable storage blocks or the like at the storage facility. Indeed, such fixed structural elements generally require special boat handling equipment capable of lifting the boat off the trailer and either shifting it laterally or supporting it in a suspended state while the trailer is moved out from under the boat.
In the Boxrud patent, the patentee attempts to minimize this problem by providing rigid but removable crossbeams which are associated with a generally U-shaped or V-shaped frame having a pair of spaced port and starboard frame members capable of being shifted towards and away from one another to accommodate boats having different hull configurations and/or beam widths. The Boxrud frame may be vertically adjusted relative to the wheel support by means of an hydraulic actuation system, although the support pads carried by the frame are not vertically adjustable with respect thereto.
A "straddle-type" small boat trailer said to be suitable for boat yard use is also disclosed in U.S. Pat. No. 3,663,040--Weaver et al. As in the Boxrud patent, the Weaver et al trailer or dolly comprises a generally U-shaped frame which requires the use of disconnectible tension means or tie bars to minimize "spreading" of the port and starboard frame members due to the weight of the boat being transported.
Other representative patents of general interest include: U.S. Pat. Nos. 3,356,239--Klein; 3,539,065--Brownell; 3,554,394--Hedman; and, 3,572,743--Parr; all of which relate to mobile boat trailers; as well as U.S. Pat. Nos. 2,547,269--Kinsey and 3,255,906--Proler et al which respectively relate to a semitrailer for transporting houses and to a system for transporting containerized materials or the like.
Although not specifically disclosed in the foregoing patents, other "straddle-type" commercial fish boat mobile dollies have been known and used in the past which employ four or more hydraulically actuated lift pads--viz., at least a fore and aft lift pad on each of the port and starboard frame members--which have been commonly controlled by an external hydraulic system often associated with the towing vehicle. Again, however, such "straddle-type" mobile dollies have been faced with serious "spreading" problems which have generally necessitated the use of removable transverse tie beams or the like. And, of course, where vertically adjustable lift pads have been provided, the "spreading" phenomenon attributable to the weight of the boat--a truly significant problem with commercial fishing boats commonly weighing up to 30,000 pounds or more--has not only been experienced with respect to the port and starboard frame members or beams of the dolly but, in addition, since the weight of the vessel is carried directly by the port and starboard lift pads, there has been a tendency for such pads to bend or spread outwardly, particularly when hydraulically extended towards or to an upper limit position, thus damaging the lift pads and preventing vertical movement thereof.